In Brazil, Anodontites trapesialis is a mussel species that occurs spontaneously in fish breeding sites. This species feeds on the remains of cultural treatments of other aquaculture species. The objective of the work is to understand the bromatological composition of mussel A. trapesialis. Individuals were selected to compose three samples of 500 g each of A. trapesialis for chemical composition, with viscera and viscera + shells being evaluated. The species presented 40.42 to 62.76 g of viscera per individual with a moisture content of 5.16% for viscera + shells and 86.5% for viscera. The mussel contains 42.6 and 12.96% crude protein, 3.16 and 1.76 of ether extract, 0.76 and 2.5% of crude fiber for viscera and viscera + shells. The total digestible nutrients were 74.16 and 36.96% for viscera and viscera + shells and 18.43 and 52.83% of mineral material for viscera and viscera + shells. A. trapesialis has relevant characteristics in its chemical composition as high protein content that gives the species potential for the human, animal, and other byproducts production.